Fluorescent amphiphilic PEG-peptide-PEG Triblock Conjugate Micelles for Cell Imaging

Abstract

A fluorescent amphiphilic poly(ethylene glycol)-peptide-fluorophore- peptide-poly(ethylene glycol) (PEG-Pep-F-Pep-PEG) triblock conjugate with a hydrophobic fluorophore moiety at the centre of the chain is synthesized by "grafting to" technique based on Schiff-base coupling chemistry. The conjugate is characterized by nuclear magnetic resonance (NMR), circular dichroism (CD), and fluorescence spectroscopy techniques. The aqueous solution of the triblock conjugate emits blue light and exhibits a fluorescence emission band at 430nm. The amphiphilic conjugate molecules undergo self-assembly into micelles (D≈15-20 nm) in aqueous solution as confirmed from transmission electron microscopy (TEM) and dynamic light scattering (DLS). The critical aggregation concentration is determined by pyrene fluorescence assay and is found to be 0.051mgmL-1. The highly stable and low toxic fluorescent PEG-Pep-F-Pep-PEG conjugate micelles are used for imaging of HeLa cells. A blue fluorescent amphiphilic poly(ethylene glycol)-peptide-fluorophore-peptide- poly(ethylene glycol) triblock conjugate is synthesized by "grafting to" technique based on Schiff base coupling chemistry, which undergo self-assembly in water to from micelles. The highly stable and low toxic conjugate micelles are used for fluorescent imaging of HeLa cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.